1. Field of the Invention
The invention relates to a tufting needle, consisting of a butt, which is capable of being integrally formed at least partially in a needle module, and of a shank, which has a needle tip, provided with an eye, and a thread guide groove on one side as well as a chamfer at one edge of the looper side located opposite the thread guide groove.
A relatively large number of tufting needles of this type are integrally formed in needle modules which, in turn, are fixed to a needle bar.
The needle modules have a bearing face which may be provided with a projecting strip. The strip may be designed as a moulded strip which engages in a groove of the needle bar. It may also be designed as a bearing strip which bears on the lower edge of the needle bar when the needle modules are fastened to the latter.
A needle module, the two sides of which are designed as a bearing face, is already known from WO 95/23 253. A bearing strip is integrally formed correspondingly on both bearing faces.
2. Background Art
German utility model 295 06 819.1 shows a needle module, likewise with two bearing faces and strips which are integrally formed on both bearing faces and which engage into a groove of the needle bar. In the above mentioned variants, therefore, the module can also be inserted in a position rotated through 180.degree.. The number of tools required can be halved in this way. There are the following technical reasons for this:
For needle modules with only one bearing face, it is necessary to keep different variants ready, depending on the intended use. This is attributable to the following cause:
When the needle module is in operation, after a basic fabric has been pricked a looper engages between the side face of the needle and the thread on one side of a tufting needle in each case and retains the thread. Loops are thereby formed when the needles are moved upwards again.
In order to minimize the wear during the interaction of loopers and needles, the needles are chamfered on this side face at a definite angle to the direction of movement of the loopers.
Depending on how the tufting machine is designed, then, appropriate module variants have to be manufactured according to whether the loopers, when they move, engage on the left or right of the needles and whether the loopers are arranged on the left or right of the needle bar, as seen in the longitudinal direction of the latter. In the case described, there are four possibilities, that is to say four different modules have to be kept ready.
By means of the modules described in the introduction and capable of being inserted in two positions, it is possible to halve the number of variants required, since one module, by being rotated, is suitable both for loopers arranged on the left of the needle bar and for those arranged on the right of the latter. In this case, two variants remain for loopers engaging in each case on the left or right side faces of the needles.